Uniform fluid distribution across a substrate during cleaning, coating, or etching processes can improve particle removal from the substrate during a cleaning process, improve the uniformity of a film applied across the substrate in a coating operation, or improve the uniformity of film layer removal from the substrate in an etching process. A rotatable base or brush core with a foam brush overlying the rotatable base or brush core can be used to distribute fluid across a substrate.
In making a rotatable base for a porous pad, and especially where the base has a high ratio of open surface area per area of base supporting the pad, exposure of the base to high temperatures in an injection molding process or during a post molding machining process can result in a loss of dimensional tolerances or dimensional stability of the rotatable base. There is a need for inexpensive, lightweight, dimensionally stable rotatable base parts that retain dimensional stability during molding and finishing operations. There is a need for inexpensive, lightweight, dimensionally stable rotatable base parts that support a porous pad, the pad being interlocked with one or more voids in the base where the base exhibits dimensional stability during use to clean substrates such as wafers or flat panel displays.